Crankcase for internal-combustion engines



Feb. 12, 1946. T. L. FAWICK 2,394,675

CRANK CASE FOR INTERNAL-COMBUSTION ENGINES 7770/770.: Fwd/ZL ATTORNEYFeb. 12, 1946. T. l.. FAWICK 2,394,675

GRANK CASE FOR INTERNAL-COMBUSTION ENGINES Filedv Jan. 30, 1942 2Sheets-Sheet 2 INVENToIg. a/mf Z. Fna/6 3 Y BY F/g v @MfG- ATTORNEYPatented Feb. 12, 1946 UNITED Is'rA'rlzs- PATENT orrlcla:4

CRANKCASE FOR lNTERNAL-COMBUSTION ENGINES Thomas L. Fawick, Akron, OhioApplication January 30, 1942, Serial No. 428,851

7 Claims. (Cl. 121-194) This invention relates to crank cases forinternal combustion engines and methods of making the same. It is ofespecial value in quantity production of crank cases for the motors ofaircraft, wherein lightness, strength, and accuracy of dimensions are futmost importance.

Because of these requisites, and because the several portions of thecrank case have to be thin but extensive in several directions, aninordinate amount of machining of large aluminum or steel forgings hasbeen required in the procedure that has been for a long time, and stillis, the general practice, in spite of the present urgent need for savingtime, labor and shipping costs and for re- Sucing waste of materials inmachining operaions.

The chief objects of this invention are economy of time and of labor,avoidance of the high cost of shipping large and heavy parts from cityto city for the forging and machining operations, the reduction of theamount of machining waste, and the provision of accuracy, lightness andstrength in the finished product.

Of the accompanying drawings:

Fig, l is a fragmentary axial section of a crank case, for a single bankof cylinders, embodying and made in accordance with my invention in itspreferred form.

Fig. 2 is a fragmentary axial section of a crank case, for two banks ofcylinders, embodying and made in accordance with my invention in itspreferred form.

Fig. 3 is a fragmentary section, on a larger scale, of parts shown inFigs. 1 and 2.

Referring first to Fig. 1, the crank case there shown comprises twoannular, somewhat bellshaped, outer members I0 and two centrallyapertured, disc-like, conical, bearing-support members II, I I, whichhave mounted in their central apertures flanged, annular seating membersI2, I2 for the crank-shaft bearings, the members I0 being adapted to besecured as by bolts III, IB to a reduction gear and propeller-bearinghousing |01 and to an engine support Ill, respectively.

Heretofore the crank case, having portions corresponding, to the fourmembers I0, I0 and II, II, have been made, integral with each other, bymachining of a single metal forging, and it is manlfest fromcontemplation of the nal shape of such a member that the machining jobis expensive, being wasteful of time, labor, material, and shippingcosts.

In the practice of my invention each of the members I0 is hot-rolled toapproximately its iinal channeled cross-sectional form,

in straight lengths, but with allowance for the relatively small amountof machining required. In this rolling operation each of the straightlengths can be long enough to provide one or several of the members I0.A single unit of the channeled stock of such length as to provide one ofthe members-IIJ being thus provided, it is then rolled to circular formand made endless by welding as at I3.

Each is then formed with semicircular notches or half-holes I 4, I4 inits margin of larger diameter, as by burning or cutting with a nametorch, with allowance for a relatively small amount of machining, toprovide holes for the mounting of the engine cylinders when two of themembers I0 are secured together as shown, by bolts I5, I5, extendingthrough holes bored in lugs I6, I6 which are the remaining portions,after the hole cutting operation, of annular internal flanges which areformed on the members I0 in the rolling operations. l

Before the members I0 are thus bolted together, however, they are sizedin suitable dies, and each has mounted in it one of the bearing-supportdisclike members I I.

Each of the members II is made by forging a billet which preferably hasits greatest dimension in the'l direction of the blows of the hammer,for providing a pronounced radial grain in the metal for the sake ofstrength. After they are hammered approximately to size and shape themembers are brought t0 a closer approximation of their final conicalform by pressing them in dies, after which they are centrally bored forreception of the bearing seats l2 and are machined at their outerperipheres to lit within the respective members I0 and againstrespective annular shoulders I1, I1 formed on the inner faces of themembers I0.

Because the outer diameter of each member II is greater than the innerdiameter of the flange of which the lugs I6 are residual parts, eachmember I I is notched as at I8, I8 to permit it to be in serted in themember I0, from the larger end of the latter, in spite of the presenceof the lugs I6.

The members I I, being mounted in the respective members I0, are thensecured in place by welding, at I9, I9, after which the assembliescomprlsing the members l0, II and I2 are bolted to each other, thecylinder holes providing access for the bolting operation.

Holes 20 forcthe valve push-rods and apertured flats 2| for the mountingof the push-rod guides can be formed at any suitable stage.

Such machining as may be desirable is performed at suitable stages ofthe procedure but it is manifest that but very little machining isrequired as compared with the procedure heretofore employed, as abovedescribed, with the result that great economy of time, labor, materialand shipbers I0 embracing it. l Each of the members l0 `oi Fig. 2hasmounted e in it a conical, disc-like, bearing-'support member Il,made and mounted in the same Way as in' Fig, 1, and at its midd1e themember In .has au somewhat similar member, A`l U, mounted incitin thesame way except that the-member H *is'uted in its radially outerportion, with the iiutes, lzlflg/ lill?, of increasing depth toward itsouter pegrip'hery, and held 'in place by weld-ing shown at 1:8, i9,on-both sides-of lits -outer margin, *the iuting thus providing ahighydegree vef strength.

]As the sinuous welds vI 9a provide strong anchorage 0f the member 'H'Ito the 'member 'H0 a sinuous shoulder on the latter is not required andconsequently A,the member 7| I-0 can be leconomically formed bysubstantially 'the same rolling operations and 'further `procedurethatareabove described as tothemembers +0 of Fig. 1.

As the Amember III ts 'against va cylindrical inner face .of the ,memberIlo which is .of sub .stantial width and asthe latters lugs, 16a,v t6?,are a yconsiderable distance' apart, the member ,Il l can be vmounted inthe member Il!) without being `.termed ,with notchesin its outer margin.

Theinvention provides .the advantages that are .set but in the .above.statement .ofobjects and -other modifications are possible Withoutsacrice ,of all Y such advantages and without departure from -thescopeef the appended claims.

Iiclai-m.: Y

1. An engine crank-,case comprising a middle annular radially-.outermetal shell member, a pair -of annular metal shell members embracing andsecured vto the same. and .metal ,bearingsupport members secured to.each .of .thethree said yshell members. Y

2. An enginefcrank-case comprising a middle annular radially-outer metalshell member, a. pair of annular metal shell members embracing and lsecured to the same, and metal bearing-support members secured to eachof the three said shell members, each of the shell members being ofrolled-metal and each of the bearing-support members being ofradially-grained metal.

3. .An uengine crank-case lcomprising :a middle annular radially-outermetal shell member, a pair of annular metal shell members embracing andksecured to the same, and metal bearing-support members secured to eachof the three said shell members, each of the shell members being ofrolled-metal and having an integral internal flange atfeach of itsmargins.

4. An 4engine ,crank-case comprising a middle 'annular radially-'outermetal shell-member, a pair of -an-nular metal shell members embracingand secured to the same, and metal bearing-support members secured ltoeach 4lof 5the three said shell members, Ieach -of the bearing-supportmembers `beingfof radially-grained metal.

y5.k An engine crank-case comprising `a middle annular radially-outermetal shellmem-ber, a pair of annular metal shell members embracing andsecured to the same, -and metal bearing-support members secured-to'ea'chof the 'three said shell members, at vleast one of the bearing-'supportlmembers being radially uted.

l6. A crank-case 'for an internal 1combustion Jengine, said crank-casecomprising 'a'pair of rolledmetal annular shell members, aradially-grained metal bearing-support member mounted in and securedtoaninneriace of each of Vthe shell-members, and means securing an annularmargin of .one Vof the shell members to an annular margin of the othershell member.

7. crank-case sub-assembly for an .internal `combustion engine, saidsub-assembly lcomprising an "annular, rolled-metal shell member'havingan internal faceV of channel form, ,and a radially grained metalbearing-support member mounted within the channel of the shell memberand se- 45 cured to a part of the said vface of channel form.

THOMAS L. FAWICK.

